Mr. Chen (courtesy name Yuan Gong) was truly a remarkable individual. He had previously authored *Shishi Milu* (Secrets of the Stone Chamber) and various books on Materia Medica, which were circulated in the world. I had privately admired and revered him for nearly twenty years. One day, while conversing with Mr. Cheng Xingxing, I learned in detail about the先生's abundant literary works, because Mr. Cheng is Mr. Yuan Gong's nephew, and thus knew him most intimately. His collected works are collectively titled *Dongyuan Quanshu* (Complete Works of the Inner Sanctum), among which none is more beneficial to humanity than *Bianzheng Lu* (Record of Syndrome Differentiation). I therefore earnestly requested it and succeeded in obtaining this book.
This compilation differentiates the similarities and differences in disease constitutions, and evaluates the attacking and tonifying properties of medicinal flavors. It applies the generation and restriction cycles of the Five Elements (Wu Xing), balancing emotional and rational considerations, making it as clear as pointing at one's palm. Even those not skilled in health preservation and guidance exercises (Daoyang), upon reading it, can know how to proceed without much confusion; this is indeed beneficial to humanity. Therefore, I exerted effort to have it carved onto printing blocks, intending to make it public throughout the land. Not only will physicians following the traditions of Xuanyuan (Yellow Emperor) and Qibo see it as a bridge to mastery, but people of all generations will also be able to engage in syndrome differentiation. Consequently, the sick shall recover, the critical shall become safe, and everyone shall live in harmony, advancing together into the realm of benevolence and longevity. This has always been my sincere aspiration.
Lou Qingchang of Yinxian respectfully wrote this postscript.